1. Manufactured full size baby cribs with dropside gates have had vertical mattress adjustments of only 8 to 9 inches for many years.
It's desirable to increase this because: (1) a new mother with a new baby needs the top of the mattress about 36 inches above the floor to eliminate stooping because an infant always goes in and comes out of the crib in a horizontal attitude and (2) as the baby grows and begins to pull up to a standing position, the top of the mattress needs to be only 18 inches above the floor which would provide maximum possible vertical wall protection.
Instead of an adjustment of 8 to 9 inches, it should be the difference between 36 and 18 or about 18 inches.
2. Description of the Prior Art
Heretofore all manufactured prior art cribs with dropside gates have used gates about 28 inches in height and these gates were provided with vertical travels of about 7 inches. The gates had only two positions full up and locked and full down and unlocked. Practice dictated that even when the gate was full down, its top should be higher than the top of the mattress for all mattress positions to provide a minimum of gate down protection.
There's good reason for these parameters being almost identical from manufacturer to manufacturer in the prior art and the reason is safety. An unintentional consequence of this is that vertical mattress adjustments are limited to just 8 or 9 inches and cannot be increased without sacrificing safety.
More recently, a Code of Federal Regulations evolved to advance crib safety and it contains sections pertaining to mattress positions.
CFR16-1508.3 (b) 1: The height of the rail and end panel as measured from the top of the rail or panel in its lowest position to the top of the mattress support in its highest position shall be at least 22.8 centimeters (9 inches). PA0 CFR16-1508.3 (b) 2: The height of the rail and end panel as measured from the top of the rail or panel in its highest position to the top of the mattress support in its lowest position shall be at least 66 centimeters (26 inches).
When the mattress is in its highest position, Regulation (b) 1 protects newborn infants in the following way. Suppose the parent has just lowered the gate to its down position and suddently an older child screams. If the parent then leaves while the infant is still in the crib, the 9 inch requirement prevents the top of the gate from being below the top of the mattress. Assuming a 51/2 inch thick mattress there is a wall of 31/2 inches in height preventing the horizontal infant from rolling to the floor even though the gate is down. The 9 inch dimension is shown at the left of FIG. 1 as HD.
When the mattress is in its lowest position, Regulation (b) 2 protects a toddler by requiring a wall height high enough to prevent the standing up toddler from falling over the top. It is desirable that the 26 inch requirement of Regulation (b) 2 be increased because after some years of Governmental and Foundational emphasis on the other elements of crib safety, most crib accidents today are the "over-the-top" accidents. The Danny Foundation, Alamo, CA, has on record incidents of precocious child "climbers" going over the top as early as 8 or 9 months of age even with Regulation (b) 2 in effect. The 26 inch requirement is shown to the left of FIG. 2 as HU.
The above background and regulations has caused the function of prior art dropside cribs to be very standard and almost identical from manufacturer to manufacturer. Because the gates are about 28 inches in height, because the gate vertical travels are about 7 inches, and because there are only two gate positions--full up and locked and full down and unlocked, the vertical mattress adjustment is restricted to just 8 to 9 inches.
Any larger vertical mattress adjustment in prior art cribs would sacrifice crib safety.